Polyamides and polyoxamides copolymerized in the presence of a glycol

ABSTRACT

Blends and/or copolymers of polyamides and polyoxamides by condensing a diamine with an ester of oxalic acid in presence of a glycol of formula HOCH2.CHOH.R where R is hydrogen lower alkyl or hydroxymethyl, and a polyamide.

[mite States- Patent [191 Oldham et al.

[4 1 Dec. 17, 1974 POLYAMIDES AND POLYOXAMIDES COPOLYMERIZED IN THEPRESENCE OF A GLYCOL [75] Inventors: Joseph Oldham, Blackley, England;Frederick Keith Duxbury, deceased,

late of Blackley, England by Jean Duxbury, administratrix [73] Assignee:Imperial Chemical Industries Limited, London, England 22 Filed: Dec. 22,1971 21 Appl. No.: 211,122

[30] Foreign Application Priority Data Dec. 22, 1970 Great Britain60902/70 [52] US. Cl 260/857 TW, 260/75 N, 260/78 R,

51 Int. Cl C08g 41/04 [58] Field of Search 260/857 TW, 78 R, 75' NPrimary Examiner--Paul Lieberman Attorney, Agenl, 0r FirmThomas J.Morgan; Robert J. Blanke [57] ABSTRACT Blends vand/or copolymers ofpolyainides and polyoxamides by condensing a diamine withan ester ofoxalic acid in presence of a glycol of formula HOCH CHOl-LR where R ishydrogen lower alkyl or hydroxymethyl, and a polyamide.

-29 Claims, N0 Drawings POEYAMIDES AND POLYOXAMIDES COPOLYMERIZED IN THEPRESENCE OF A I GLYCOL This invention relates to polyamides and moreespecially to blends and copolymers of polyamides and polyoxamides andto methods fortheir'manufacture.

It is already known to prepare blends of polyamides and polyoxamides byblending the two components together in the molten state. It has alsobeen proposed in our British Pat. Specification No. 1252073, to obtainpolyoxamides of sufficiently high molecular weight to be capable ofbeing melt spun into filaments by carrying out the condensation of adiamine with an ester of oxalic acid in the presence of ethylene glycolor certain substituted derivatives thereof.

We have now found 7 a novel and advantageous method of preparing blendsand/or copolymers of polyamides and polyoxamides which comprisescarrying out the condensation of a diamine with an ester of oxalic acidin the presence of a solution or mixture of a polyamide with ethyleneglycol or certain substituted derivatives thereof.

According to our invention we provide a process for the manufacture. ofblends and/or copolymers of polyamides and polyoxamides which comprisescondensing a diamine with an ester of. oxalic acid by heating them inthe presence of a glycol and a polyamide, the glycol having the generalformula in which R represents a hydrogen atom, a lower alkyl grouphaving from 1 to 4 carbon atoms or a hydroxymethyl group. I

The diamines which may be used in the condensation with the oxalicesters may be any diamine customarily used in the manufacture ofpolyamides byreaction with dicarboxylic acids or amide-formingderivatives thereof. Suitable diamines includealiphatic,cycloaliphatic-or varaliphatic diamines, especiallyalkylene diamines andparticularly those having at -least two carbon'atoms joining the aminogroups thereof. Suitable 2 or di-n-butyl oxalate is particularlypreferred. Diphenyl oxalate may also be used.

The glycols in the presence of which the diamines and oxalic esters arecondensed by heating have the formula cu oucnoua in which R is ahydrogen atom, a lower alkyl group having up to 4 carbon atoms or ahydroxymethyl group. Ethylene glycol is preferred, but, for example,1,2-propylene glycol or 1,2-butylene glycol may be used.

As polyamides there may be used any polyamide it is desired to blend orcopolymerise with a polyoxamide. Such polyamides are the condensationproducts which contain recurring amide groups as integral parts of themain polymer chain and are known generically as the nylons. These areobtained in known manner by polymerising an amino carboxylic acid or itsderived lactam in which there are at least two .carbon atoms between theamino and carboxylic acid group; or by condensing substantiallyequimolecular proportions of a diamine which contains at least twocarbon atoms between the amino groups with a dicarboxylic acid otherthan oxalic acid. 7 i

The aminocarboxylic acids are preferably those having between 2 and 16carbon atoms between the amino and carboxylic acid groups, their derivedlactams forming a ring containing from 2 to 16 carbon atoms in additionto a CO.NH- group. As particular examples of such compounds there may bementioned 6 -aminocaproic acid, capr'olactam, butyrolactam,pivalolactam, capryllactam, enantholactam, undecanolactam anddodecanolactam, which are used in the process of our invention in theform of their polymers.

adipic acid, pimelic acid, suberic acid, azelaic acid, se-

diamines include those represented by the-formula densation with thediamines are usually aliphatic esters,

especially the dialkyl esters and particularly the dilower alkyl esterscontaining up to 4 carbon atoms in the alcoholic portion. As particularexamples of such esters there may be mentioned dimethyl, diethyl, di-.isopropyl, di-n-propyl and di-n-butyl oxalate. Diethyl Diamines whichmay be condensed with dicarboxylic acids other than oxalic acid to givepolyamides for use in the process of our invention may beany of thosementioned above for use in the condensation with the oxalic ester.Suitable dicarboxylic acids include aliphatic-dicarboxylic acidsespeciallyalkylene dicarboxylic containing from 2 to lo carbon atoms inthe alkylene residue. As examples of such dicarboxylic acids there maybe mentioned succinic acid, glutaric acid,

bacic acid, undecanedioic acid and dodecanedioic acid. Aromaticdicarboxylic acids may also be used, for example isophthalic acid orterephthalic acid.

As well as polyamides, mixtures of polyamides or copolyamides may beused in the process of our inven'- tion. As examples of suitablepolyamides there maybe mentioned polyhexamethylene adipamide,polyhexamethylene sebacamid e, polyhexamethylene azelaamide,polyhexamethylene isophthalamide, polyhexa methylene terephthalamide,poly-m-xylylene adipamide, polycaprolactam, polyundecanolactam,

polydodecanolactam and copolymersof hexamethylene adipamide andcaprolactam.

In the process of our invention the diamine and the oxalic ester areheated in the presence of the glycol and the polyamide. The temperatureof heating is preferably at least high enough for the polyamide todissolve appreciably in the glycol. We have found that when.

polyamides are dissolved in the glycol, glycolysis oc-' curs, that istosay amide groups of the polymer chain are split with the formation ofglycol ester end groups and amino end groups; for example in the case ofethylene glycol the following reaction takes place The temperature atwhich this reaction takes place to an appreciable extent will varysomewhat depending on the nature of the glycol and the particularpolyamide used. In the case of ethylene glycol and polyhexamethyleneadipamide a temperature greater than 160C is necessary for appreciablesolution of the polyamide in the glycol. Contrary to the behaviour ofthe polyamides, however, when polyoxamide-forming components are heatedin the glycol at these temperatures polycondensation to form thepolyoxamide proceeds smoothly.

A preferred method of carrying out the process of our invention is toheat the polyamide in the glycol until partial or total solution occurs,then add the oxalic ester, and after an interval add the diamine andcontinue heating until the desired reaction has taken place. When theoxalic. ester is added to the solution of the polyamide in the glycol,reaction of the oxalic ester with the amino groups formed duringsolution of the polyamide occurs, with liberation of the alcohol of theoxalic ester. The interval between adding the oxalic ester andsubsequently adding the diamine in our preferred process may vary but isnormally between 5 minutes and 5 hours.

The total time of heating may vary widely depending on the nature of thereactants and the temperature employed. Times of heating normally fallwithin the range 3 hours to 24 hours. Longer times of heating are, ofcourse, possible, but degradationof the resulting polymer is liable tooccur if heating is unduly prolonged. Temperatures of heating may rangefrom about 150C up to 200C or higher. It is an advantage of ourinvention, however, that the products are obtained at only moderatelyelevated temperatures, whereas previous methods of obtaining blends ofpolyamides and polyoxamides required mixing the components at atemperature above their melting points, that is to say at temperatureswithin the region of 200 to 330C. As a result of products being formedat lower temperatures there is less risk of degradation and products ofbetter colour are obtained. 1n the process of our invention, therefore,we prefer to heat the reactants at temperatures not exceeding 180C.

The process of our invention also has the advantage over a melt blendingprocess that a more homogeneous 1 product is obtained.

After the reaction is complete the product may be isolated, for example,by cooling to about 120C, filtering and washing, for example with waterand/or methanol, and drying. Alternatively, the reaction mixture may bepoured into water and the product filtered off, washed and dried.

Because of the glycolysis of the polyamide in the process of ourinvention, the product will normally contain some copolymer in additionto polyamide and polyoxamide blended together.

The diamine and oxalic ester are normally used in substantiallyequivalent amounts. The proportion of polyamide to polyoxamide formingcomponents may vary between 1:10 and 10:1 by weight. The proportion ofglycol to the total of polyamide and polyoxamideforming components mayvary between 30/1 and 2/1 by weight, with proportions between 25/1 and4/1 being preferred.

The blends and/or copolymers of polyamides and polyoxamides may be meltspun into filaments or fibres, and may be formed into shaped articles bymoulding, extrusion or other shaping processes.

We have found that polyoxamides containing from 10 to 25% by weight ofpolyamide made by the process of our invention yield fibres havingphysical properties similar to those of fibres obtained from thepolyoxamides themselves but which are easier to spin and have improvedaffinity for dyestuffs, especially acid dyestuffs.

Particularly useful products of the process of our invention are theproducts obtained when the diamine is a mixture oftrimethylhexamethylene diamine and hexamethylene diamine, especially inthe molar proportions of from 60/40 to 20/80, and the polyamide ispolyhexamethylene adipamide, the proportion of polyamide being from 10%to by weight. The trimethylhexamethylene diamine is preferably a mixtureof the 2,2,4 and 2,4,4-isomers in approximately equal proportions. Alsoparticularly useful are the products obtained when the diamine ishexamethylene diamine and the polyamide is polyhexamethylene adipamide,the proportion of polyamide being from 60% to 80% by weight.

If desired the products of the process of our invention may containadditives, which may conveniently be added-to the ingredients before orduring the reaction, for example delustrants such as titanium dioxide,pigments such as carbon black or copper phthalocyanine, heatstabilisers, light stabilisers and molecular weight regulators.

The invention is illustrated but not limited by the following Examplesin which the parts and percentages are by weight.

EXAMPLE 1 152 Parts of nylon 6,6 polymer (polyhexamethylene adipamide)(inherent viscosity 1.06 in concentrated sulphuric acid) were dissolvedin 2,500 parts of ethylene glycol by stirring at 180C for 30 minutes.The solution was cooled to C and 365.5 parts of diethyl oxalate addedfollowed by 16 parts of a 10% w/w dispersion of titanium .dioxide inethylene glycol and 0.5 parts of zinc oxide. After 10'minutes 451.1parts of diamine mixture was added over 12 minutes.

The diamine mixture consisted of 159.6 parts of mixed 2,2,4- and2,4,4-trimethylhexamethylene diamine (50/50 ratio) and 291.5 parts ofa60% by weight methyl alcohol solution of hexamethylene diamine.

The temperature was raised to C over 1 hour whilst the alcohols addedand formed in the reaction are distilled off. After heating at 160 C for3 hours the reaction mixture was cooled to 100C and poured into water.The precipitated product was filtered, washed free from glycol withwater and methyl alcohol and dried. The product had an inherentviscosity (1V) in sulphuricacid of 0.68, amine end value 133 and a meltviscosity at 276C of 585 poise.

The product was a trimethyl hexamethylene diaminelhexamethylene diamine(40/60) copolyoxamide containing 25% of nylon 6,6 polymer.

The product was extruded into monofil at 290C and then spun intofilaments which were drawn at a draw at 180C.

The filaments had a tenacity of 4.6 grams per denier (g.p.d.) at 15%extension, an initial modulus of 48 g.p.d. before, and 38 g.p.d. afterboiling in water for one-half hour. The work recovery was 93% andelastic recovery 97.5% after stretching 2% and relaxing. The stressdecay value was 19% and shrinkage in boiling water 8.7%.

For nylon 6,6 the initial modulus was 33.0 before, and 16.6 afterboiling in water, work recovery 79.9%,

weight'composition which comprises condensing a diamine with an ester ofoxalic acid in the presence of a glycol, and in the presence of from 10%to 80% by elastic recovery 93.4%, stress decay 40% and shrinkage 10Weight of a p lyamid aid polyamide being in Solution in boiling water13.7%. g in said glycol, the glycol having the following formula:

For the unblended polyoxamide from 40/60 mol ratio of mixedtrimethylhexamethylene diamine (TMD) and hexamethylene diamine (HMD) thefibre properties were initial modulus 49.4 before and 39.6 afterboiling, Ho-011F0 1. work recovery 96%, elastic recovery 99%, stressdecay III 17.5% and shrinkage in boiling water 8.1%.

EXAMPLES 2 to 4 wherein R represents a hydrogen atom, a lower alkylProducts of the composition and properties given in g p ing o 1 t0 4Carbon ms r a hydroxythe following table were made by the general methodmethyl g p y heating at 2 mp re f nt r described in Example 1.copolymerization of said'polyamide with said glycol,

Example Mol. Ratio of Wt. n ion-6,6 lnitial modulus Work Elastic StressTMD/HMD in copolyin b end before boiling After boiling Recovery RecoveryDecay oxamide segment g.p.d. g.p.d I 2 40/60 1O 50 37.6 V 94 98.9 19.7 340/60 50 43.6 23.6 86 94 27,5 4 40/60 75 38.4 23.2 84.6 95 35.5

The products of Examples 1 to 4 could be melt spun but in any event at atemperature not greater than faster and with fewer fibre breakages thanthe 40/60 180C, saidpolyamide being a polyamide obtained by ratiocopolyoxamide alone. The fibres dyed equally polymerizing an aminocarboxylic acid or its derivative well with disperse dyestuffs as thecopolyoxamide but i 5 lactam in which there are at least two carbonatoms beto a greater depth with acid dyestuffs: tween the amino andcarboxylic acid group,,or by con- I densing substantially equimole'cularproportions of a EXAMPLE 5 diamine which contains at least two carbonatoms be- 153 parts of nylon 6,6 were added to 3000 parts of tween theamino g p With a dtcatboxyhc acid Other ethylene glycol at 170C anddissolved in minutes. than OXahC, the P P h of g y t0 the total of SaidThe solution was cooled to 160C and 002 parts zinc polyamide and saidester of oxalic acid being between oxide added followed by 14.6 parts ofdiethyl oxalate. 30:1 and 2:1 by weight acid. 7 After stirring for 3hours at l60-165C, 19.05 parts of 2. A'process according to claim 1wherein the dia 60% solution of hexamethylene diamine in methyl alamineis an aliphatic, cycloaliphatic or araliphatic dicohol was added over 15minutes. The mixture was amine. stirred at 165C for. 3 hours then cooledto room tem- 3. A process according to claim 1 wherein the diperature,filtered and washed free from glycol. amineis an alkylene diamine.

The product had an 1.V. of0.57, amine end value 4. A process accordingto claim 3 wherein the alkyl- 133, and showed peaks on adifferentialscanning colorene is of at least 2 carbon atomslength between the imeterat 251, 260 and 269C but not at the oxamide amino groups. peak of 339C;It consists of 10% of polyhexameth- 5. A process according to claim 4wherein the diylene oxamide incorporated in nylon 6,6. amine is of theformula I Nl-l .C,.l-1 HN or HN (CH ),,NH wherein n is an integer from 2to 16.

EXAMPLE- 6 6. A process according to claim 1 wherein the di- This wasmade similarly to Example 5, but 20% of amine is'hexamethylenediaminehexamethylene diamine polyoxamide (6,2) was incor- APYOCGSSaccording to Claim wherein the P y" porated in nylon 6,6. The producthad 1.V. 0.52 and amide 1S Polyhexamethylehe adipamlde h Proportionpeaks on a differential scanningcolorimeter' at 250 0f p yamide beingfrom to 80%,by weight. d 257C 8. A process according to claim 1 whereinthe di- EXAMPLE 60 amine is a'mixture of trimethylhexamethylene diamine1 and hexamethylene diam ne and the polyamide ls poly- 40% ofpolyoxamide 6,2 was incorporated into nylon hexamethylene adipamide 76,6 as in E p The Product had peaks on a diffet- I 9.-A processaccording to claim 8 wherein the molar ential scanning colorimeter at247, 259and 300C. proportions f the two i i are f 60/40 to The resultson the differential scanning colorimeter ,20/80,

for Examples 5 to 7 show that the polyoxamide is incorporated into theother polyamide anddoes not exist as 10. A process according to c1aim 8in which the trimethylhexamethylene diamine is a mixture of the 2:2:4-and 2:4:4-isomers in approximately equal proportions.

11. A process according to claim 1 wherein the ester of oxalic acid is adialkyl ester.

12. A process according to claim 11 wherein alkyl contains 2 or 4 carbonatoms.

13. A process according to claim 11 wherein alkyl is ethyl or n-butyl.

14. A process according to claim 1 wherein the ester of oxalic acid isdiphenyl oxalate.

15. A process according to claim 1 wherein in the glycol R is methyl orethyl.

16. A process according to claim 1 wherein in the glycol R is hydrogen.

17. A process according to claim 1 wherein the polyamide used asreactant is derived from an aminocarboxylic acid havinga chain of from 2to 16 carbon atoms between the amino and carboxyl groups.

18. A process according to claim 1 wherein the polyamide used asreactant is derived from a diamine of the formula NH .C,,H ,,.NH or HN(CH ),,NH where n is an integer from 2 to 16 and a dicarboxylic acid.

19. A process according to claim 18 wherein the diamine is hexamethylenediamine.

20. A process according to claim 18 wherein the dicarboxylic acid is analkylene dicarboxylic acid in which the alkylene is from 2 to 16 carbonatoms.

21. A process according to claim 18 wherein the dicarboxylic acid is anaromatic dicarboxylic acid.

22. A process according to claim 21 wherein the aromatic dicarboxylicacid is isophthalic acid or terephthalic acid.

23. A process according to claim 1 wherein the glycol is ethyleneglycol, the polyamide is polyhexamethylene adipamide and the temperatureat which the reaction is carried out is at least C.

24. A process according to claim 1 wherein the interval of time betweenaddition of the oxalic ester and of the diamine is at least 5 minutesand not exceeding 5 hours.

25. A process according to claim 1 wherein the total time of reaction isfrom 3 hours to 24 hours.

26. A process according to claim 1 wherein the proportion of glycol tototal of polyamide and polyoxamide-forming components is from 25 to l to4 to l.

27. A proces according to claim 1 wherein the proportion of polyamide topolyoxamide forming components is from 1 to lOto 10 to 1.

28. A process according to claim 1 wherein said high molecular weightcomposition contains from 10% to 25% by weight of polyamide.

29. The process of claim 1 wherein said .high molecular weightcomposition is hot-melt extruded.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,855,350Dated December 17, 1974 Inventor(s) Joseph oldhamp derick It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Claim 1, ultimate line, delete the word "acid".

I 0 II II' Claim 5, line 2, cancel the formula NH .C H .,HN andsubstitute therefore the formula NH .C H .NH

Claim 5, line 3, cancel the formula "BN (CH NH and substitute thereforethe formula NH @H NH n l I Claim 18, line 3, cancel the phrase 'NH .C H.NH or HN (CH NH and substitute therefore the phrase 2 NH .C H .NH orNH2 ('CI[-I NH Signed and sealed this lst 'day of April 1975.

(SEAL) Attest:

H C. I-IARSHALL DANN RUTH C ILASON- Commissioner of Patents ArrestingOfficer and Trademarks

1. A PROCESS FOR THE MANUFACTURE OF A HIGH MOLECULAR WEIGHT COMPOSITIONWHICH COMPRISES CONDENSING A DIAMINE WITH AB ESTER OF OXALIC ACID IN THEPRESENCE OF A GLYCOL, AND IN THE PRESENCE OF FROM 10% TO 80% BY WEIGHTOF A POLYAMIDE SAID POLYAMIDE BEING IN SOLUTION IN SAID GLYCOL, THEGLYCOL HAVING THE FOLLOWING FORMULA:
 2. A process according to claim 1wherein the diamine is an aliphatic, cycloaliphatic or araliphaticdiamine.
 3. A process according to claim 1 wherein the diamine is analkylene diamine.
 4. A process according to claim 3 wherein the alkyleneis of at least 2 carbon atoms length between the amino groups.
 5. Aprocess according to claim 4 wherein the diamine is of the formulaNH2.CnH2n.HN2 or HN2(CH2)nNH2, wherein n is an integer from 2 to
 16. 6.A process according to claim 1 wherein the diamine is hexamethylenediamine.
 7. A process according to claim 6 wherein the polyamide ispolyhexamethylene adipamide, the proportion of polyamide being from 60to 80% by weight.
 8. A proceSs according to claim 1 wherein the diamineis a mixture of trimethylhexamethylene diamine and hexamethylene diamineand the polyamide is polyhexamethylene adipamide.
 9. A process accordingto claim 8 wherein the molar proportions of the two diamines are from60/40 to 20/80.
 10. A process according to claim 8 in which thetrimethylhexamethylene diamine is a mixture of the 2:2:4- and 2:4:4-isomers in approximately equal proportions.
 11. A process accordingto claim 1 wherein the ester of oxalic acid is a dialkyl ester.
 12. Aprocess according to claim 11 wherein alkyl contains 2 or 4 carbonatoms.
 13. A process according to claim 11 wherein alkyl is ethyl orn-butyl.
 14. A process according to claim 1 wherein the ester of oxalicacid is diphenyl oxalate.
 15. A process according to claim 1 wherein inthe glycol R is methyl or ethyl.
 16. A process according to claim 1wherein in the glycol R is hydrogen.
 17. A process according to claim 1wherein the polyamide used as reactant is derived from anaminocarboxylic acid having a chain of from 2 to 16 carbon atoms betweenthe amino and carboxyl groups.
 18. A process according to claim 1wherein the polyamide used as reactant is derived from a diamine of theformula NH2.CnH2n.NH2 or HN2(CH2)nNH2, where n is an integer from 2 to16 and a dicarboxylic acid.
 19. A process according to claim 18 whereinthe diamine is hexamethylene diamine.
 20. A process according to claim18 wherein the dicarboxylic acid is an alkylene dicarboxylic acid inwhich the alkylene is from 2 to 16 carbon atoms.
 21. A process accordingto claim 18 wherein the dicarboxylic acid is an aromatic dicarboxylicacid.
 22. A process according to claim 21 wherein the aromaticdicarboxylic acid is isophthalic acid or terephthalic acid.
 23. Aprocess according to claim 1 wherein the glycol is ethylene glycol, thepolyamide is polyhexamethylene adipamide and the temperature at whichthe reaction is carried out is at least 160*C.
 24. A process accordingto claim 1 wherein the interval of time between addition of the oxalicester and of the diamine is at least 5 minutes and not exceeding 5hours.
 25. A process according to claim 1 wherein the total time ofreaction is from 3 hours to 24 hours.
 26. A process according to claim 1wherein the proportion of glycol to total of polyamide andpolyoxamide-forming components is from 25 to 1 to 4 to
 1. 27. A procesaccording to claim 1 wherein the proportion of polyamide to polyoxamideforming components is from 1 to 10 to 10 to
 1. 28. A process accordingto claim 1 wherein said high molecular weight composition contains from10% to 25% by weight of polyamide.
 29. The process of claim 1 whereinsaid high molecular weight composition is hot-melt extruded.